A magnetic memory device is a kind of a non-volatile memory device in which data is programmed or erased using a magnetic field. With the potential benefits of high speed, low density, and/or non-volatility, magnetic memory devices are increasingly becoming attractive as novel memory devices.
A typical magnetic memory device employs a magnetic tunnel junction (MTJ) pattern as a data storage element. The resistance of the MTJ pattern varies with an external magnetic field, which leads to a change in the amount of current flowing through the MTJ pattern. The change in the amount of the current is sensed to indicate a logic “1” or a logic “0”.
Generally, an MTJ pattern includes two magnetic layers and a tunnel barrier layer interposed therebetween. One of the magnetic layers has a changeable magnetization orientation when a magnetic field is applied, while the other has a fixed magnetization orientation even when a magnetic field is applied. Therefore, the two magnetic layers may have the same magnetization orientation or opposite magnetization orientations. The resistance of the MTJ pattern in which the two magnetic layers have the same magnetization orientation is lower than when the two magnetic layers are in different magnetization orientations.
A method of forming a conventional magnetic memory device will now be described with reference to FIG. 1 and FIG. 2.
Referring to FIG. 1, a bottom magnetic layer 2, a tunnel barrier layer 3, a top magnetic layer 4, and a conductive capping layer 5 are formed in order on a substrate 1. The bottom magnetic layer 2 has a fixed magnetization orientation. That is, the magnetization orientation of the bottom magnetic layer 2 may be continuously fixed even when an external magnetic field is applied. Furthermore, the magnetization orientation of the top magnetic layer 4 is changeable with an external magnetic field.
Referring to FIG. 2, the conductive capping layer 5, the top magnetic layer 4, the tunnel barrier layer 3, and the bottom magnetic layer 2 are successively patterned to form a bottom magnetic pattern 2a, a tunnel barrier pattern 3a, a top magnetic pattern 4a, and a capping pattern 5a that are stacked in order on the substrate 1. The bottom magnetic pattern 2a, the tunnel barrier pattern 3a, and the top magnetic pattern 4a form a MTJ pattern.
During an etch process to form the MTJ pattern, an etch byproduct 6 may be produced on a sidewall of the MTJ pattern. Since the etch byproduct 6 may include conductive materials from the bottom and/or top magnetic patterns 2a and 5a, it may become conductive, which may cause a short-circuit between the bottom and top magnetic patterns 2a and 5a. Thus, the desired property of the MTJ pattern (namely, that the resistance varies with the magnetization orientations of the magnetic patterns 2a and 5a) may be lost, which may result in a malfunction of the magnetic memory device.